Display device and method of reparing the same

ABSTRACT

Provided are a display device in which a bright spot occurring due to a defective pixel circuit may be repaired into a dark spot, and a method of repairing the display device. The display device includes a substrate, a thin-film transistor arranged on the substrate and including a semiconductor layer and a gate electrode overlapping at least a portion of the semiconductor layer, a pixel electrode on the substrate, a node connection line connecting the thin-film transistor and the pixel electrode to each other, and an initialization voltage line arranged on the substrate and extending in a first direction, wherein the node connection line includes a repair portion overlapping the initialization voltage line in a plan view.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. § 119to Korean Patent Application No. 10-2021-0054632, filed on Apr. 27,2021, in the Korean Intellectual Property Office, the disclosure ofwhich is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

The present disclosure generally relates to a display device. Moreparticularly, the present disclosure relates to a display device havinga structure capable of a darkening repair when a bright spot defectoccurs, and a method of repairing the display device.

2. Description of the Related Art

Display devices provide visual information such as images or videos to auser. With the development of various electronic devices such astelevisions, computers, mobile phones, and tablet personal computers(PCs), display devices of various types applicable thereto have beendeveloped.

Such a display device includes a scan line and a data line insulatedfrom each other, and includes a plurality of pixel circuits connected tothe scan line and the data line. Each of the pixel circuits includes aplurality of thin-film transistors and a storage capacitor, and maydrive a light-emitting element.

Meanwhile, in a process of manufacturing the display device, a defectmay occur in some pixel circuits. A defect, for example, a short-circuitor opening of a thin-film transistor or a signal line of a pixel circuitmay occur.

SUMMARY

When a defect occurs in a pixel circuit, a light-emitting element drivenby the defective pixel circuit may always generate light regardless of ascan signal and a data signal. A pixel always emitting light asdescribed above may be recognized as a bright spot to a user, causing abright spot defect of the display device. In particular, with the recentincrease in size and high resolution of display devices, the possibilityof such a defect in the pixel circuit and a bright spot defect of thedisplay device has increased.

To resolve various problems including the above issues, one or moreembodiments include a display device capable of making the displaydevice into a normal product by repairing bright spots occurring due toa defective pixel circuit into dark spots, and a method of repairing thedisplay device. However, these objectives are examples and do not limitthe scope of the present disclosure.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the embodiments of the present disclosure.

According to an embodiment, a display device includes a substrate, athin-film transistor arranged on the substrate and including asemiconductor layer and a gate electrode overlapping at least a portionof the semiconductor layer, a pixel electrode arranged on the substrate,a node connection line configured to connect the thin-film transistorand the pixel electrode to each other, and an initialization voltageline arranged on the substrate and extending in a first direction,wherein the node connection line includes a repair portion overlappingthe initialization voltage line in a plan view.

The display device may further include a data line arranged on thesubstrate and extending in the first direction, and the initializationvoltage line may be arranged closer to the thin-film transistor than thedata line in a plan view.

The node connection line may not overlap the data line in a plan view.

The display device may further include a storage capacitor including afirst capacitor plate and a second capacitor plate overlapping eachother, and the first capacitor plate and the gate electrode of thethin-film transistor may include a same material, and the secondcapacitor plate may include a portion of the node connection line.

The display device may further include a bottom metal layer arrangedbetween the substrate and the semiconductor layer of the thin-filmtransistor.

The initialization voltage line and the bottom metal layer may include asame material.

The display device may further include a storage capacitor including afirst capacitor plate and a third capacitor plate overlapping eachother, and the first capacitor plate and the gate electrode of thethin-film transistor may include a same material, and the thirdcapacitor plate may include a portion of the bottom metal layer.

The repair portion of the node connection line may be connected to theinitialization voltage line through a contact hole.

The display device may further include a scan line extending in a seconddirection crossing the first direction, and a branch line extending inthe first direction from the scan line.

The scan line, the branch line, and the gate electrode of the thin-filmtransistor may include a same material.

The display device may further include an opposite electrode arranged onthe pixel electrode, and an emission layer arranged between the pixelelectrode and the opposite electrode.

The display device may further include an auxiliary line disposedbetween the repair portion of the node connection line and theinitialization voltage line, and electrically connected to theinitialization voltage line.

The auxiliary line and the gate electrode of the thin-film transistormay include a same material.

The repair portion of the node connection line may be electricallyconnected to the initialization voltage line through the auxiliary line.

According to an embodiment, a display device includes a substrate, athin-film transistor arranged on the substrate and including asemiconductor layer and a gate electrode overlapping at least a portionof the semiconductor layer, an initialization voltage line arranged onthe substrate and extending in a first direction, a pixel electrodearranged on the substrate and electrically connected to the thin-filmtransistor, and an upper insulating film arranged on the pixelelectrode, and including an opening corresponding to a portion of thepixel electrode, wherein the pixel electrode includes a repair portionoverlapping the initialization voltage line in a plan view, and therepair portion does not overlap the opening of the upper insulatingfilm.

The display device may further include a data line arranged on thesubstrate and extending in the first direction, and the initializationvoltage line may be arranged between the data line and the thin-filmtransistor.

The display device may further include a bottom metal layer arrangedbetween the substrate and the semiconductor layer of the thin-filmtransistor, and the initialization voltage line and the bottom metallayer may include a same material.

The repair portion of the pixel electrode may be connected to theinitialization voltage line through a contact hole.

According to an embodiment, a method of repairing a display device whichincludes a substrate, a thin-film transistor arranged on the substrateand comprising a semiconductor layer and a gate electrode overlapping atleast a portion of the semiconductor layer, a pixel electrode on thesubstrate, an initialization voltage line arranged on the substrate andextending in a first direction, and a node connection line electricallyconnecting the thin-film transistor and the pixel electrode to eachother, and including a repair portion overlapping the initial voltageline in a plan view, wherein the method includes short-circuiting therepair portion of the node connection line and the initializationvoltage line to each other.

The short-circuiting of the repair portion of the node connection lineand the initialization voltage line to each other may be accomplished byirradiating a laser beam to an area in which the repair portion of thenode connection line and the initialization voltage line overlap eachother.

Other aspects, features, and advantages other than those described abovewill become apparent from the accompanying drawings, the appendedclaims, and the detailed description of the disclosure.

These general and specific aspects may be carried out using a system, amethod, a computer program, or any combinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments will be more apparent from the following description takenin conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view schematically illustrating a display deviceaccording to an embodiment;

FIG. 2 is a cross-sectional view schematically illustrating a portion ofa display device according to an embodiment;

FIG. 3 is an enlarged schematic cross-sectional view of a portion of acolor-conversion-transmitting layer of a display device according to anembodiment;

FIG. 4A is an equivalent circuit diagram of a pixel circuit provided ina display device according to an embodiment;

FIG. 4B is an equivalent circuit diagram of a pixel circuit after aprocess of repairing of a display device is performed, according to anembodiment;

FIG. 5 is a plan view schematically illustrating a portion of a displaydevice according to an embodiment;

FIG. 6 is a cross-sectional view schematically illustrating a portion ofa display device according to an embodiment;

FIGS. 7A and 7B are cross-sectional views schematically illustratingoperations of a method of repairing a display device, according to anembodiment;

FIG. 8 is a plan view schematically illustrating a portion of a displaydevice according to another embodiment;

FIG. 9 is a cross-sectional view schematically illustrating across-section of the display device in FIG. 8, taken along line IX-IX′in FIG. 8;

FIG. 10 is a cross-sectional view schematically illustrating across-section of the display device in FIG. 9 after a process ofrepairing of the display device, according to an embodiment;

FIG. 11 is a cross-sectional view schematically illustrating across-section of a display device according to another embodiment; and

FIG. 12 is a cross-sectional view schematically illustrating across-section of the display device in FIG. 11 after a process ofrepairing of the display device, according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout the present disclosure. Inthis regard, the present embodiments may have different forms andconfiguration and should not be construed as being limited to thedescriptions set forth herein. Accordingly, the embodiments are merelydescribed below, by referring to the figures, to explain aspects of thepresent disclosure. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.Throughout the present disclosure, the expression “at least one of a, bor c” indicates only a, only b, only c, both a and b, both a and c, bothb and c, all of a, b, and c, or any variations thereof.

Because the present disclosure may have diverse modified embodiments,embodiments are illustrated in the drawings and are described withrespect to the embodiments. An effect and a characteristic of thepresent disclosure, and a method of accomplishing them will be apparentby referring to embodiments described with reference to the drawings.The present disclosure may, however, be embodied in many different formsand configurations and should not be construed as limited to theembodiments set forth herein.

One or more embodiments of the present disclosure will be describedbelow in more detail with reference to the accompanying drawings.Components that are the same or are in correspondence with each otherare rendered the same reference numeral regardless of the figure number,and redundant explanations are omitted.

In an embodiment below, terms such as “first” and “second” are usedherein merely to describe a variety of constituent elements, but theconstituent elements are not limited by the terms. Such terms are usedonly for the purpose of distinguishing one constituent element fromanother constituent element.

An expression used in the singular encompasses an expression of theplural unless the context expressly indicates otherwise.

It will be understood that the terms “comprises” and/or “comprising”used herein specify the presence of stated features or elements, but donot preclude the presence or addition of one or more other features orelements.

It will be further understood that when a layer, area, or element isreferred to as being “formed on” another layer, area, or element, it canbe directly or indirectly formed on the other layer, region, or element.That is, for example, one or more intervening layers, areas, or elementsmay be present therebetween.

In the drawings, sizes of components in the drawings may be exaggeratedor reduced for convenience of explanation. In other words, because sizesand thicknesses of components in the drawings are arbitrarilyillustrated for convenience of explanation, the following embodimentsare not limited thereto.

When an embodiment may be implemented differently, a certain processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

In the present disclosure, the term “and/or” includes any and allcombinations of one or more of the associated listed items. For example,“A and/or B” may include “A,” “B,” or “A and B.” Throughout the presentdisclosure, the expression “at least one of a, b, or c” indicates onlya, only b, only c, both a and b, both a and c, both b and c, all of a,b, and c, or any variations thereof.

It will be understood that when a layer, region, or component isreferred to as being connected to another layer, region, or component,it can be directly or indirectly connected to the other layer, region,or component. That is, for example, intervening layers, regions, orcomponents may be present. For example, when layers, areas, or elementsor the like are referred to as being “electrically connected,” they maybe directly electrically connected, or layers, areas or elements may beindirectly electrically connected, and an intervening layer, region,component, or the like may be present therebetween.

The x-axis, the y-axis, and the z-axis are not limited to three axes ofa rectangular coordinate system, and may be interpreted in a broadersense. For example, the x-axis, the y-axis, and the z-axis may beperpendicular to one another, or may represent different directions thatare not perpendicular to one another.

FIG. 1 is a perspective view schematically illustrating a display device1 according to an embodiment.

Referring to FIG. 1, the display device 1 may include a display area DAand a peripheral area PA outside of the display area DA. The displayarea DA may include an area in which an image is provided. The displaydevice 1 may provide an image through an array of a plurality of pixelsPX arranged in the display area DA. Each of the pixels PX includes anarea from which light of a color may be emitted, and the display device1 may provide an image using light emitted by the pixels PX. Forexample, each of the pixels PX may emit red, green, or blue light.

A light-emitting element generating light and a pixel circuit fordriving the light-emitting element may be arranged in the display areaDA. In addition, a data line and a scan line that are electricallyconnected to the pixel circuit may be arranged in the display area DA.

The peripheral area PA includes an area that does not provide an image,and may entirely or partially surround the display area DA. Variouspower lines, signal lines, and a driving circuit which provideelectrical signals or power to the pixel circuit in the display area DAmay be arranged in the peripheral area PA. In addition, a pad unit towhich an electronic component or a printed circuit board may beelectrically connected may be arranged in the peripheral area PA.

When viewed from a direction perpendicular to one surface of the displaydevice 1, the display device 1 may have a substantially rectangularshape. For example, as shown in FIG. 1, the display device 1 may have anoverall rectangular planar shape having, for example, a long sideextending in an x direction and a short side extending in a y direction.A corner at which the short side in the x direction and the long side inthe y direction meet may have a right-angled shape or may have a roundshape having a curvature. However, a planar shape of the display device1 is not limited to a rectangular shape, and may include various shapes,such as a polygonal shape such as a triangular shape, a circular shape,an oval shape, an amorphous shape, or the like.

In FIG. 1, the display device 1 has a flat display surface, but theexample is not limited thereto. In another embodiment, the displaydevice 1 may include a three-dimensional display surface or a curveddisplay surface. When the display device 1 includes thethree-dimensional display surface, the display device 1 may include aplurality of display areas indicating different directions, and mayinclude, for example, a polygonal column type display surface. Inanother embodiment, when the display device 1 includes the curveddisplay surface, the display device 1 may be implemented in variousforms including flexible, foldable, rollable display devices.

In some embodiments, the display device 1 may include a light-emittingunit 10 and a color unit 20 that are stacked in a thickness directionthereof (for example, a z direction). The light-emitting unit 10 mayinclude a light-emitting element and a pixel circuit. The color unit 20may include a color filter layer and a color-conversion-transmittinglayer. This will be described in detail below, with reference to FIG. 2.

Meanwhile, the display device 1 may be used as a display screen not onlyin portable electronic devices, such as mobile phones, smart phones,tablet PCs, mobile communication terminals, electronic notebooks,electronic books, portable multimedia players (PMPs), navigations, andultra mobile PCs (UMPCs), but also in various products such astelevisions, laptops, monitors, billboards, and Internet of things(IoT). In addition, the display device 1 according to an embodiment maybe used in wearable devices, such as smart watches, watch phones,glasses-type displays, and head mounted displays (HMDs). In addition,the display device 1 may be used as instrument panels for automobiles,center fascias for automobiles, or center information displays (CIDs)arranged on a dashboard, room mirror displays that replace side mirrorsof automobiles, and displays arranged on the rear side of front seats asentertainment for rear seats of automobiles.

FIG. 2 is a cross-sectional view schematically illustrating a portion ofthe display device 1 according to an embodiment. FIG. 2 may correspondto a cross-section of the display device 1 in FIG. 1, taken along lineII-II′ in FIG. 1.

Referring to FIG. 2, the display device 1 may include a light-emittingunit 10 and a color unit 20. The light-emitting unit 10 includes alight-emitting element generating light, and may include a plurality oforganic light-emitting diodes OLED. In addition, the light-emitting unit10 may include pixel circuits PC electrically respectively connected tothe plurality of organic light-emitting diodes OLED. For example, thelight-emitting unit 10 may include first, second, and third organiclight-emitting diodes OLED1, OLED2, and OLED3 and first, second, andthird pixel circuits PC1, PC2, and PC3 respectively connected thereto.

Each of the organic light-emitting diodes OLED of the light-emittingunit 10 may be driven by a corresponding pixel circuit PC, and may emitlight toward the color unit 20. The light emitted from thelight-emitting unit 10 may be implemented as light of various colors viathe color unit 20.

The color unit 20 may be arranged on the light-emitting unit 10, and mayinclude a color-conversion-transmitting layer 400 and a color filterlayer 500. For example, the color-conversion-transmitting layer 400 ofthe color unit 20 may be arranged on a corresponding organiclight-emitting diode OLED, and the color filter layer 500 may bearranged on the color-conversion-transmitting layer 400.

The color-conversion-transmitting layer 400 may include a firstcolor-conversion unit 410, a second color-conversion unit 420, and alight-transmitting unit 430. The first color-conversion unit 410, thesecond color-conversion unit 420, and the light-transmitting unit 430may be arranged to correspond to the first, second, and third organiclight-emitting diodes OLED1, OLED2, and OLED3, respectively. The firstcolor-conversion unit 410, the second color-conversion unit 420, and thelight-transmitting unit 430 may convert incident light of a first colorfrom the light-emitting unit 10 into light of a second color differentfrom the first color, or may transmit the incident light of the firstcolor without color conversion. In an embodiment, for example, bluelight Lb may be emitted from the first, second, and third organiclight-emitting diodes OLED1, OLED2, and OLED3. The blue light Lb may beconverted into red light Lr or green light Lg via the color unit 20, ormay be transmitted as blue light Lb without color conversion. In thiscase, for example, the red light Lr may include light in a wavelengthband of about 580 nm to about 780 nm, the green light Lg may includelight in a wavelength band of about 495 nm to about 580 nm, and the bluelight Lb may include light in a wavelength band of about 400 nm to about495 nm.

The color filter layer 500 may include a first color filter layer 510, asecond color filter layer 520, and a third color filter layer 530 thatselectively transmit light of different colors. The first color filterlayer 510, the second color filter layer 520, and the third color filterlayer 530 may be arranged to correspond to the first color-conversionunit 410, the second color-conversion unit 420, and thelight-transmitting unit 430, respectively.

For example, the red light Lr, the green light Lg, and the blue light Lbwhich are color-converted or transmitted by thecolor-conversion-transmitting layer 400 may have improved color purityby passing through the first, second, and third color filter layers 510,520, and 530, respectively, and then, may be emitted to the outside ofthe display device 1. An area from which the red light Lr is emitted maycorrespond to a first pixel PX1, an area from which the green light Lgis emitted may correspond to a second pixel PX2, and an area from whichthe blue light Lb is emitted may correspond to a third pixel PX3. Thus,the display device 1 may provide a full color image.

So far, an example in which a light-emitting element of the displaydevice 1 includes an organic light-emitting diode OLED including anorganic emission layer is described. However, the present disclosure isnot limited thereto. In another embodiment, the light-emitting elementmay include an inorganic light-emitting diode including an inorganicmaterial. The inorganic light-emitting diode may include a p-n diodeincluding materials based on an inorganic material semiconductor. When avoltage is applied to the p-n junction diode in a forward direction, ahole and an electron are injected, and light of a color may be emittedby converting energy created due to recombination of the hole and theelectron to light energy. The inorganic light-emitting diode may have awidth ranging from several to hundreds of micrometers. In anotherembodiment, the light-emitting element may include quantum dots as anemission layer. However, in the following description, a case where thelight-emitting element includes an organic light-emitting diode OLEDwill be mainly described, for convenience of explanation.

FIG. 3 is an enlarged schematic cross-sectional view of a portion of thecolor-conversion-transmitting layer 400 of a display device according toan embodiment.

Referring to FIG. 3, the color-conversion-transmitting layer 400 mayinclude a first color-conversion unit 410, a second color-conversionunit 420, and a light-transmitting unit 430.

For example, the first color-conversion unit 410 may convert blue lightLb into red light Lr. To this end, the first color-conversion unit 410may include a first photosensitive polymer 411 in which first quantumdots 412 are dispersed.

The first photosensitive polymer 411 is not particularly limited as longas the material has excellent dispersibility and light transmittance,but may include, for example, an acryl-based resin, an imide-basedresin, or an epoxy-based resin.

The first quantum dots 412 may be excited by the blue light Lb, and mayisotropically emit the red light Lr having a wavelength longer than thatof the blue light Lb. In the disclosure, a quantum dot refers to acrystal of a semiconductor compound, and may include any materialcapable of emitting light in various wavelength bands depending on asize of the crystal.

The first quantum dots 412 may be synthesized by a wet chemical process,an organic metal chemical vapor deposition process, a molecular beamepitaxy process, or a similar process. The wet chemical process is amethod of growing quantum dot particle crystals after mixing an organicsolvent with a precursor material. When the crystal is grown, theorganic solvent acts as a dispersant naturally coordinated on a quantumdot crystal surface, and adjusts a growth of the crystal, and thus, thewet chemical process is easier than a vapor deposition method such asmetal organic chemical vapor deposition (MOCVD) or molecular beamepitaxy (MBE), and through a low-cost process, a growth of quantumparticles may be controlled.

The first quantum dots 412 may include a Group III-VI semiconductorcompound, a Group II-VI semiconductor compound, a Group III-Vsemiconductor compound, a Group III-VI semiconductor compound, a GroupI-III-VI semiconductor compound, a Group IV-VI semiconductor compound, aGroup IV element or compound, or any combinations thereof.

For example, the Group III-VI semiconductor compounds may include abinary compound such as In₂S₃, a ternary compound such as AgInS, AgInS₂,CuInS, and CuInS₂, or any combinations thereof.

Examples of the Group II-VI semiconductor compound may include: a binarycompound such as Cds, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe,MgSe, and MgS; a ternary compound such as CdSeS, CdSeTe, CdSTe, ZnSeS,ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS,CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, and MgZnS; a quaternarycompound such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe,HgZnSeS, HgZnSeTe, and HgZnSTe; or any combinations thereof.

Examples of the Group III-V semiconductor compound may include: a binarycompound such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP,InAs, and InSb; a ternary compound such as GaNP, GaNAs, GaNSb, GaPAs,GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs,InNSb, InPAs, InPSb, and GaAlNP; a quaternary compound such as GaAlNAs,GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb,InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; or any combinationsthereof. Meanwhile, the Group III-V semiconductor compound may furtherinclude a Group II element. Examples of the Group III-V semiconductorcompound further including the Group II element may include InZnP,InGaZnP, InAlZnP, or the like.

Examples of the Group III-VI semiconductor compound may include: abinary compound such as GaS, GaSe, Ga₂Se₃, GaTe, InS, InSe, In₂Se₃, andInTe; a ternary compound such as InGaS₃ and InGaSe₃; or any combinationsthereof.

Examples of the Group I-III-VI semiconductor compound may include aternary compound such as AgInS, AgInS₂, CuInS, CuInS₂, CuGaO₂, AgGaO₂,and AgAlO₂, or any combinations thereof.

Examples of the Group IV-VI semiconductor compound may include: a binarycompound such as SnS, SnSe, SnTe, PbS, PbSe, and PbTe; a ternarycompound such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS,SnPbSe, and SnPbTe; a quaternary compound such as; SnPbSSe, SnPbSeTe,and SnPbSTe; or any combinations thereof.

The Group IV element or compound may include: a single element compoundsuch as Si and Ge; a binary compound such as SiC and SiGe; or anycombinations thereof.

Each of elements included in the multi-element compound, such as thebinary compound, the ternary compound, and the quaternary compound, maybe present in a particle in a uniform or non-uniform concentration.

Meanwhile, the first quantum dots 412 may have a single structure or acore-shell dual structure in which a concentration of each elementincluded in the corresponding quantum dot is uniform. For example, amaterial included in the core and a material included in the shell maybe different from each other.

The shell may serve as a protective layer for maintaining semiconductorproperties by preventing chemical modification of the core and/or as acharging layer for imparting electrophoretic properties to quantum dots.The shell may include a single layer or multiple layers. An interfacebetween the core and the shell may have a concentration gradient inwhich the concentration of elements in the shell decreases toward thecenter of the core.

Examples of the shell may include a metal or non-metal oxide, asemiconductor compound, or any combinations thereof. Examples of themetal or non-metal oxide may include: a binary compound such as SiO₂,Al₂O₃, TiO₂, ZnO, MnO, Mn₂O₃, Mn₃O₄, CuO, FeO, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄,and NiO; a ternary compound such as MgAl₂O₄, CoFe₂O₄, NiFe₂O₄, CoMn₂O₄;or any combinations thereof. Examples of the semiconductor compound mayinclude: a Group III-VI semiconductor compound; a Group II-VIsemiconductor compound; a Group III-V semiconductor compound; a GroupIII-VI semiconductor compound; a Group I-III-VI semiconductor compound;a Group IV-VI semiconductor compound; or any combinations thereof. Forexample, the semiconductor compound may include CdS, CdSe, CdTe, ZnS,ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP,InGaP, InSb, AlAs, AlP, AlSb, or any combinations thereof.

The first quantum dots 412 may have a full width of half maximum (FWHM)of an emission wavelength spectrum in a range of about 45 nm or less,for example, about 40 nm or less, and for example, about 30 nm or less.Color purity or color reproducibility may be improved in this range.Also, because light emitted from the first quantum dots 412 is emittedin all directions, an optical viewing angle may be improved.

In addition, a shape of the first quantum dots 412 is specificallyspherical, pyramidal, multi-arm, or cubic nanoparticles, nanotubes,nanowires, nanofibers, nanoplatelet particles, etc. First scatteringparticles 413 may be further dispersed in the first photosensitivepolymer 411. The first scattering particles 413 may allow more firstquantum dots 412 to be excited by scattering the blue light Lb that isnot absorbed by the first quantum dots 412. Thus, the color-conversionefficiency of the first color-conversion unit 410 may be increased. Inaddition, the first scattering particles 413 may scatter light invarious directions regardless of an incident angle without substantiallyconverting a wavelength of the incident light. Thus, side visibility maybe improved.

The first scattering particles 413 may include a particle having arefractive index different from that of the first photosensitive polymer411, for example, a light-scattering particle. The first scatteringparticles 413 are not particularly limited as long as the material mayform an optical interface with the first photosensitive polymer 411 andpartially scatter transmissive light, but may include, for example,metal oxide particles or organic particles. For example, the metal oxidemay include titanium oxide (TiO₂), zirconium dioxide (ZrO₂), aluminumoxide (Al₂O₃), indium oxide (In₂O₃), zinc oxide (ZnO), or tin oxide(SnO₂), and the organic materials may include an acryl-based resin or aurethane-based resin. The second color-conversion unit 420 may convertthe blue light Lb into the green light Lg. The second color-conversionunit 420 may include a second photosensitive polymer 421 in which secondquantum dots 422 are dispersed, and second scattering particles 423 aredispersed together with the second quantum dots 422 in the secondphotosensitive polymer 421, thus increasing a color conversion rate ofthe second color-conversion unit 420.

The second photosensitive polymer 421 and the first photosensitivepolymer 411 may include the same material, and the second scatteringparticles 423 and the first scattering particles 413 may include thesame material.

The second quantum dots 422 may include the same material as the firstquantum dots 412, and may have the same shape as the first quantum dots412. However, a size of the second quantum dots 422 may be less than asize of the first quantum dots 412. This is to allow the second quantumdots 422 to emit light in a wavelength band different from that of thefirst quantum dots 412. For example, an energy band gap may be adjustedby adjusting a size of quantum dots, and thus, light in variouswavelength bands may be obtained. The second quantum dots 422 have asize less than that of the first quantum dots 412, and thus, the secondquantum dots 422 are excited by the blue light Lb and have a wavelengthlonger than that of the blue light Lb, and may isotropically emit thegreen light Lg having a wavelength shorter than that of the red lightLr. The light-transmitting unit 430 may include a third photosensitivepolymer 431 in which third scattering particles 433 are dispersed. Inother words, the light-transmitting unit 430 does not include anadditional quantum dot that may be excited by the blue light Lb.Meanwhile, like the first photosensitive polymer 411, the thirdphotosensitive polymer 431 may include an organic material having alight transmittance, and the third scattering particles 433 may includethe same material as the first scattering particles 413. Thus, bluelight Lb incident on the light-transmitting unit 430 may transmit thelight-transmitting unit 430 without color change, and thus, lightemitted through the light-transmitting unit 430 may be blue light Lb.However, the blue light Lb may be scattered by the third scatteringparticles 433 within the light-transmitting unit 430, and may be emittedto the outside. The light-transmitting unit 430 may transmit the bluelight Lb incident thereon without color change, thus obtaining improvedlight efficiency.

FIG. 4A is an equivalent circuit diagram of a pixel circuit PC providedin a display device according to an embodiment. FIG. 4B is an equivalentcircuit diagram of the pixel circuit PC after a process of repairing ofa display device is performed, according to an embodiment.

Firstly, referring to FIG. 4A, the pixel circuit PC may include aplurality of thin-film transistors and at least one capacitor. In anembodiment, the pixel circuit PC may include a first thin-filmtransistor T1, a second thin-film transistor T2, a third thin-filmtransistor T3, and a storage capacitor Cst.

Each of the first thin-film transistor T1, the second thin-filmtransistor T2, and the third thin-film transistor T3 may include anoxide semiconductor thin-film transistor including a semiconductor layerincluding an oxide semiconductor, or may include a silicon semiconductorthin-film transistor including a semiconductor layer includingpolysilicon. Each of the first, second, and third thin-film transistorsT1, T2, and T3 may include a first electrode and a second electrode, andthe first electrode may be one of a source electrode and a drainelectrode, and the second electrode may be the other one of the sourceelectrode and the drain electrode, depending on a type of the thin-filmtransistor. In addition, each of the first, second, and third thin-filmtransistors T1, T2, and T3 may include a gate electrode.

The first thin-film transistor T1 may include a driving thin-filmtransistor. The first electrode of the first thin-film transistor T1 maybe connected to a driving voltage line VDL for applying a driving powervoltage ELVDD, and the second electrode of the first thin-filmtransistor T1 may be connected to a pixel electrode of an organiclight-emitting diode OLED. The gate electrode of the first thin-filmtransistor T1 may be connected to a first node N1. The first thin-filmtransistor T1 may control an amount of current flowing from the drivingpower voltage ELVDD through the organic light-emitting diode OLED inresponse to a voltage of the first node N1.

The second thin-film transistor T2 may include a switching thin-filmtransistor. The first electrode of the second thin-film transistor T2may be connected to a data line DL, and the second electrode of thesecond thin-film transistor T2 may be connected to the first node N1.The gate electrode of the second thin-film transistor T2 may beconnected to a scan line SL. When a scan signal is transmitted to thescan line SL, the second thin-film transistor T2 may be turned on, andmay electrically connect the data line DL and the first node N1 to eachother.

The third thin-film transistor T3 may include an initializationthin-film transistor and/or a sensing thin-film transistor. The firstelectrode of the third thin-film transistor T3 may be connected to asecond node N2, and the second electrode of the third thin-filmtransistor T3 may be connected to an initialization voltage line INL.The gate electrode of the third thin-film transistor T3 may be connectedto the scan line SL.

The third thin-film transistor T3 may be turned on when a scan signal istransmitted to the scan line SL, and may electrically connect theinitialization voltage line INL and the second node N2 to each other. Insome embodiments, the third thin-film transistor T3 may be turned onaccording to a signal received via the scan line SL, and may initializethe pixel electrode of the organic light-emitting diode OLED by using aninitialization voltage from the initialization voltage line INL.

In some embodiments, the third thin-film transistor T3 may be turned onwhen a scan signal is transmitted to the scan line SL, to sensecharacteristic information of the organic light-emitting diode OLED. Thethird thin-film transistor T3 may have both a function of theinitialization thin-film transistor and a function of the sensingthin-film transistor, or may have a function of either one. Aninitialization operation and a sensing operation of the third thin-filmtransistor T3 may be performed individually or simultaneously. When thethird thin-film transistor T3 has the function of the sensing thin-filmtransistor, the initialization voltage line INL may be referred to as asensing line.

The storage capacitor Cst may be connected between the first node N1 andthe second node N2. For example, a first capacitor plate of the storagecapacitor Cst may be connected to the gate electrode of the firstthin-film transistor T1, and a second capacitor plate of the storagecapacitor Cst may be connected to the pixel electrode of the organiclight-emitting diode OLED.

An opposite electrode of the organic light-emitting diode OLED may beconnected to a common voltage line VSL for providing a common powervoltage ELVSS.

In FIG. 4, the pixel circuit PC includes three thin-film transistors andone storage capacitor, but the present disclosure is not limitedthereto. In another embodiment, the number of thin-film transistors andthe number of storage capacitors may be variously modified depending onthe design of the pixel circuit PC.

Meanwhile, in a process of manufacturing the display device 1 (see FIG.1), a defect may occur in some pixel circuits PC. For example, a defectin which the first thin-film transistor T1 may be shorted may occur dueto a foreign material or a process error. In this case, the organiclight-emitting diode OLED may always receive the driving power voltageELVDD regardless of a scan signal and a data signal, and thus, mayalways emit light. As the organic light-emitting diode OLED always emitslight, a corresponding pixel PX (see FIG. 1) may always be recognized asa bright spot to a user. In general, when at least one such bright spotis present in the display device 1, the display device 1 may be treatedas defective as a whole (this defect is hereinafter referred to as abright spot defect).

Referring to FIG. 4B, a bright spot may be changed to a dark spot byrepairing a pixel circuit PC having a defect. As described above, whenat least one defective bright spot is present in the display device 1,the display device 1 is treated as defective as a whole, but apredetermined number of dark spots present in the display device 1 maybe allowed.

In an embodiment, the initialization voltage line INL and the secondnode N2 may be shorted in the pixel circuit PC having a defect. UnlikeFIG. 4A, FIG. 4B shows a short-circuit path ST disposed between theinitialization voltage line INL and the second node N2. In this case, aninitialization voltage may always be applied to the second node N2 thatis directly connected to the initialization voltage line INL. Theinitialization voltage line INL transfers an initialization voltage (forexample, about 2 volts), which is less than a voltage for illuminatingthe organic light-emitting diode OLED (for example, about 8 volts), andthus, the organic light-emitting diode OLED does not always emit lightregardless of a data signal and a scan signal, and a corresponding pixelPX may include a dark spot.

As described above, a defective bright spot may be changed to a darkspot through repair of the pixel circuit PC, thus reducing treatment ofthe entire display device 1 as defective. Thus, the productivity andyield of the display device 1 may increase.

FIG. 5 is a plan view schematically illustrating pixel circuits providedin a display device 1 according to an embodiment.

Referring to FIG. 5, the display device 1 may include a plurality ofpixel circuits PC. For example, the display device 1 may include first,second, and third pixel circuits PC1, PC2, and PC3. In addition, thedisplay device 1 may include various lines electrically connected toeach of the pixel circuits PC, for example, a scan line SL, a pluralityof data lines DL, a branch line BL, an initialization voltage line INL,a driving voltage line VDL, and a common voltage line VSL.

In an embodiment, for example, the scan line SL may extend in an xdirection, and the plurality of data lines DL may extend in a ydirection crossing the x direction. The branch line BL may extend in they direction from the scan line SL. Each of the initialization voltageline INL, the driving voltage line VDL, and the common voltage line VSLmay extend in the y direction.

In some embodiments, the driving voltage line VDL and the common voltageline VSL are spaced apart from each other, and the plurality of datalines DL may be arranged between the driving voltage line VDL and thecommon voltage line VSL. The plurality of data lines DL may include, forexample, first to third data lines DL1, DL2, and DL3, and the first,second, and third data lines DL1, DL2, and DL3 may be arranged adjacentto each other and adjacent to the common voltage line VSL. The first,second, and third data lines DL1, DL2, and DL3 may apply independentdata signals to the first, second, and third pixel circuits PC1, PC2,and PC3, respectively.

In an embodiment, the initialization voltage line INL and the branchline BL may be arranged between the driving voltage line VDL and thecommon voltage line VSL. The initialization voltage line INL may bearranged between a first thin-film transistor T1 to be described later,and the data line DL. The branch line BL may be arranged at an oppositeside to the data line DL with respect to the initialization voltage lineINL. For example, the branch line BL may be integrally formed as asingle body with the scan line SL, and may transfer a scan signaltogether with the scan line SL.

The arrangement of the first, second, and third data lines DL1, DL2, andDL3, the initialization voltage line INL, and the branch line BL in FIG.5 is only an example, and the present disclosure is not limited thereto,and the arrangement may be appropriately changed and modified accordingto the design of the pixel circuit PC.

The display device 1 may include a structure in which the structureshown in FIG. 5 is repeated in the x direction and the y direction.Thus, a plurality of scan lines SL and a plurality of driving voltagelines VDL provided in the display device 1 may form a mesh structure ina plan view. Likewise, the plurality of scan lines SL and a plurality ofcommon voltage lines VSL may form a mesh structure in a plan view. Here,the expression “in a plan view” may refer to “on a virtual planeparallel to the substrate 100 (see FIG. 6) of the display device 1.”

A plurality of thin-film transistors, for example, first, second, andthird thin-film transistors T1, T2, and T3, and a storage capacitor Cstmay be arranged in a space surrounded by the scan lines SL adjacent toeach other in a plan view, the driving voltage line VDL, and the commonvoltage line VSL. The plurality of thin-film transistors, for example,the first, second, and third thin-film transistors T1, T2, and T3, andthe storage capacitor Cst may be included in one pixel circuit PC. Forexample, the first to third pixel circuits PC1, PC2, and PC3 shown inFIG. 5 may include the first to third thin-film transistors T1, T2, andT3, respectively, and may each include the storage capacitor Cst.Hereinafter, for convenience of explanation, a structure and arrangementof the plurality of thin-film transistors, for example, first, second,and third thin-film transistors T1, T2, and T3, and the storagecapacitor Cst provided in the first pixel circuit PC1 will be mainlydescribed. The second pixel circuit PC2 and the third pixel circuit PC3have the same structure and arrangement as the first pixel circuit PC1described above, except that the second pixel circuit PC2 and the thirdpixel circuit PC3 are respectively connected to the second data line DL2and the third data line DL3. Thus, redundant descriptions of the secondpixel circuit PC2 and the third pixel circuit PC3 will be omitted.

Each of the thin-film transistors, for example, the first, second, andthird thin-film transistors T1, T2, and T3, of the first pixel circuitPC1 may include a semiconductor layer and a gate electrode overlappingat least a portion of the semiconductor layer.

The first thin-film transistor T1 may include a first semiconductorlayer A1 and a first gate electrode G1 overlapping at least a portion ofthe first semiconductor layer A1. The first semiconductor layer A1 mayinclude an oxide semiconductor or a silicon-based semiconductor. Thefirst semiconductor layer A1 may include a channel area, and a sourcearea and a drain area respectively arranged at opposite sides of thechannel area. The source area and the drain area are areas having alower resistance than the channel area, and may be formed through adoping process or a conductorization process of impurities. The sourcearea and the drain area may correspond to a source electrode and a drainelectrode of each thin-film transistor, respectively. Hereinafter, forconvenience of explanation, terms “a source area” and “a drain area” areused instead of “a source electrode” or “a drain electrode.” A firstgate electrode G1 may overlap the channel area of a first semiconductorlayer A1.

In the first semiconductor layer A1, one of the source area and thedrain area may be electrically connected to the driving voltage line VDLthrough a first contact hole CNT1, and the other one may be electricallyconnected to the storage capacitor Cst through a second contact holeCNT2. For example, the first semiconductor layer A1 may be connected toa second capacitor plate CE2 of the storage capacitor Cst through thesecond contact hole CNT2.

The second thin-film transistor T2 may include a second semiconductorlayer A2 and a second gate electrode G2 overlapping at least a portionof the second semiconductor layer A2. The second semiconductor layer A2may include an oxide semiconductor or a silicon-based semiconductor. Thesecond semiconductor layer A2 may include a channel area, and a sourcearea and a drain area respectively arranged at opposite sides of thechannel area. The second gate electrode G2 may overlap the channel areaof the second semiconductor layer A2. The second gate electrode G2 maycorrespond to a portion of the scan line SL or a portion of the branchline BL extending in the y direction from the scan line SL as shown inFIG. 5.

One of the source area and the drain area of the second semiconductorlayer A2 may be electrically connected to the storage capacitor Cst, andthe other one may be electrically connected to the data line DL. Forexample, the second semiconductor layer A2 may be connected to a firstconnection line CL1 through a fourth contact hole CNT4, and the firstconnection line CL1 may be connected to a first capacitor plate CE1 ofthe storage capacitor Cst through a third contact hole CNT3. Inaddition, the second semiconductor layer A2 may be connected to a secondconnection line CL2 through a fifth contact hole CNT5, and the secondconnection line CL2 may be connected to the first data line DL1 througha sixth contact hole CNT6.

The third thin-film transistor T3 may include a third semiconductorlayer A3 and a third gate electrode G3 overlapping at least a portion ofthe third semiconductor layer A3. The third semiconductor layer A3 mayinclude an oxide semiconductor or a silicon-based semiconductor. Thethird semiconductor layer A3 may include a channel area and a sourcearea and a drain area respectively arranged at opposite sides of thechannel area. The third gate electrode G3 may overlap the channel areaof the third semiconductor layer A3. The third gate electrode G3 maycorrespond to a portion of the scan line SL or a portion of the branchline BL extending in the y direction from the scan line SL as shown inFIG. 5.

One of the source area and the drain area of the third semiconductorlayer A3 may be electrically connected to the initialization voltageline INL, and the other one may be electrically connected to the storagecapacitor Cst. For example, the third semiconductor layer A3 may beconnected to a third connection line CL3 through an eighth contact holeCNT8, and the third connection line CL3 may be connected to theinitialization voltage line INL through a seventh contact hole CNT7. Inaddition, the third semiconductor layer A3 may be connected to thesecond capacitor plate CE2 of the storage capacitor Cst through a ninthcontact hole CNT9.

The storage capacitor Cst may include at least two capacitor plates thatoverlap each other. In an embodiment, the storage capacitor Cst mayinclude the first capacitor plate CE1 and the second capacitor plate CE2overlapping each other. In some embodiments, the storage capacitor Cstmay further include a third capacitor plate CE3 that overlaps the firstcapacitor plate CE1 and the second capacitor plate CE2.

The first capacitor plate CE1 may be integrally provided as a singlebody with the first gate electrode G1. In other words, a portion of thefirst capacitor plate CE1 may correspond to the first gate electrode G1.The second capacitor plate CE2 may be arranged on the first capacitorplate CE1 in a cross-sectional view, and may correspond to a portion ofa node connection line NCL. In other words, the node connection line NCLmay include the second capacitor plate CE2. The third capacitor plateCE3 may be arranged below the first capacitor plate CE1 in across-sectional view, and may correspond to a portion of a bottom metallayer BML. In other words, the bottom metal layer BML may include thethird capacitor plate CE3. The second capacitor plate CE2 may beelectrically connected to the third capacitor plate CE3 through a tenthcontact hole CNT10. Here, the expression “in a cross-sectional view” mayrefer to “on a virtual plane perpendicular to a substrate 100 (see FIG.6) of the display device 1.”

The node connection line NCL may electrically connect the firstthin-film transistor T1 with a pixel electrode of an organiclight-emitting diode. For example, the node connection line NCL may beconnected to the first thin-film transistor T1 through the secondcontact hole CNT2, and although not shown in FIG. 5, a pixel electrode210 (see FIG. 6) of an organic light-emitting diode OLED (see FIG. 6)may be connected to the node connection line NCL through a contact holeand/or a connection electrode. In addition, the node connection line NCLmay be electrically connected to the third thin-film transistor T3. Forexample, the node connection line NCL may be connected to the thirdthin-film transistor T3 through the ninth contact hole CNT9. The nodeconnection line NCL may correspond to the second node N2 in FIGS. 4A and4B described above.

In an embodiment, the node connection line NCL may include not only thesecond capacitor plate CE2 of the storage capacitor Cst, but also arepair portion RP. At least a portion of the repair portion RP mayoverlap the initialization voltage line INL in a cross-sectional view.For example, the repair portion RP of the node connection line NCL mayextend in the x direction crossing the y direction, which is anextension direction of the initialization voltage line INL, and mayoverlap the initialization voltage line INL. That is, the repair portionRP of the node connection line NCL overlaps at least a portion of theinitialization voltage line INL. An area in which the repair portion RPand the initialization voltage line INL overlap each other in a planview may be defined as a repair area RA.

According to an embodiment, when a defect occurs in the first pixelcircuit PC1, the repair portion RP of the node connection line NCL andthe initialization voltage line INL may be shorted to each other. Forexample, by irradiating a laser beam to the repair area RA in which therepair portion RP and the initialization voltage line INL overlap eachother, the repair portion RP and the initialization voltage line INL maybe shorted to each other. In this case, the initialization voltage lineINL may not go through the third thin-film transistor T3, but may applyan initialization voltage to the pixel electrode 210 of the organiclight-emitting diode OLED. Accordingly, the organic light-emitting diodeOLED may not always emit light, and a corresponding pixel PX may includea dark spot. Thus, a bright spot defect may be resolved.

In a comparative example, a laser beam may be irradiated to a pluralityof areas to resolve a bright spot defect. For example, by irradiating alaser beam to various areas, a process in which some lines are openedand other lines are shorted may be performed.

However, according to an embodiment, a laser beam is irradiated only toa single area, thereby resolving a bright spot defect. Thus, a repairprocess time may be reduced, and a repair success rate may be improved.Thus, the productivity and yield of the display device 1 may beimproved. In addition, according to an embodiment, it is not necessaryto open lines of the pixel circuit PC for repair. Accordingly, it isunnecessary to ensure a space margin for opening when designing thepixel circuit PC, and thus, design restrictions are minimized, therebyimproving the degree of integration and resolution of the display device1.

Meanwhile, according to an embodiment, the initialization voltage lineINL may be arranged closer to the first, second, and third thin-filmtransistors T1, T2, and T3 than the data line DL in a plan view. Forexample, the initialization voltage line INL may be arranged closer tothe first thin-film transistor T1 than the first, second, and third datalines DL1, DL2, and DL3 in a plan view. The node connection line NCL maynot overlap the data line DL in a plan view. For example, the repairportion RP of the node connection line NCL extends in the x direction,but only up to an area in which the initialization voltage line INL isarranged. Thus, the repair portion RP of the node connection line NCLmay overlap only the initialization voltage line INL, and not the dataline DL. Thus, the occurrence of parasitic capacitance and couplingbetween the node connection line NCL and the data line DL may beminimized.

Hereinafter, a stacked structure of the display device 1 will bedescribed with reference to FIG. 6.

FIG. 6 is a cross-sectional view schematically illustrating a portion ofthe display device 1 in FIG. 5 according to an embodiment, taken alongline VI-VI′ in FIG. 5.

Referring to FIG. 6, the display device 1 may include the substrate 100,and various elements of the display device 1 to be described later maybe arranged on the substrate 100.

The substrate 100 may include glass, a metal, or a polymer resin. Whenthe substrate 100 is flexible or bendable, the substrate 100 may includea polymer resin such as, for example, polyethersulfone, polyacrylate,polyetherimide, polyethylene naphthalate, polyethylene terephthalate,polyphenylene sulfide, polyarylate, polyimide, polycarbonate, orcellulose acetate propionate. However, the substrate 100 may have amulti-layer structure including two layers each including the polymerresin described above and a barrier layer including an inorganicmaterial (such as silicon oxide, silicon nitride, or siliconoxynitride), between the layers, and various modifications may be made.

A plurality of thin-film transistors may be arranged on the substrate100. FIG. 6 shows a cross-section of the first thin-film transistor T1as an example, and hereinafter, for convenience of explanation, astacked structure of a thin-film transistor in a cross-sectional viewwill be described with a focus on the first thin-film transistor T1. Astacked structure of the second and third thin-film transistors T2 andT3 (see FIG. 5) in a cross-sectional view may be same or similar as orto that of the first thin-film transistor T1.

The first thin-film transistor T1 may include the first semiconductorlayer A1 and the first gate electrode G1 overlapping at least portion ofthe first semiconductor layer A1.

The first semiconductor layer A1 of the first thin-film transistor T1may include, for example, an oxide semiconductor. The oxidesemiconductor may include indium gallium zinc oxide (IGZO), zinc tinoxide (ZTO), zinc indium oxide (ZlO), or the like. In another example,the first semiconductor layer A1 may include polysilicon, amorphoussilicon, or an organic semiconductor.

The first gate electrode G1 of the first thin-film transistor T1 mayoverlap the channel area of the first semiconductor layer A1 with a gateinsulating layer 112 therebetween. The first gate electrode G1 mayinclude, for example, a conductive material including molybdenum (Mo),aluminum (A1), copper (Cu), titanium (Ti), or the like, and may beprovided as multiple layers or a single layer including the materialsdescribed above. In some embodiments, the first gate electrode G1 mayhave a multi-layer structure of a metal layer including the metalelements described above, and a transparent conductive oxide layerincluding ITO, on the metal layer.

The first capacitor plate CE1 of the storage capacitor Cst may be formedin the same process as the first gate electrode G1, and may include thesame material as the first gate electrode G1. In addition, the branchline BL and the scan line SL (see FIG. 5) integrally provided as asingle body with the branch line BL may be formed in the same process asthe first gate electrode G1, and may include the same material as thefirst gate electrode G1.

The gate insulating layer 112 may be arranged below the first gateelectrode G1, the first capacitor plate CE1, and the branch line BL. Thegate insulating layer 112 may be formed in the same mask process as thefirst gate electrode G1, the first capacitor plate CE1, and the branchline BL. Thus, the gate insulating layer 112 may have a planar shapethat is substantially same as those of the first gate electrode G1, thefirst capacitor plate CE1, and the branch line BL. For example, the gateinsulating layer 112 may include an inorganic material such as siliconoxide, silicon nitride, and/or silicon oxynitride.

The bottom metal layer BML may be disposed between the substrate 100 andthe first semiconductor layer A1 of the first thin-film transistor T1.For example, the bottom metal layer BML may be arranged directly on anupper surface of the substrate 100. The bottom metal layer BML mayinclude one or more materials from among A1, platinum (Pt), palladium(Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium(Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), Mo, andCu. In some embodiments, the bottom metal layer BML may include alight-shielding material. The bottom metal layer BML may overlap thefirst thin-film transistor T1. In some embodiments, a constant voltageor a signal may be applied to the bottom metal layer BML. The bottommetal layer BML may improve and/or stabilize characteristics of thefirst thin-film transistor T1.

In an embodiment, the bottom metal layer BML may include the thirdcapacitor plate CE3 of the storage capacitor Cst. In other words, thethird capacitor plate CE3 of the storage capacitor Cst may be providedas a portion of the bottom metal layer BML. Thus, a space may be usedefficiently, and a degree of integration of the display device 1 may beimproved.

In an embodiment, the data lines DL and the initialization voltage lineINL may be arranged on the substrate 100. The data lines DL and theinitialization voltage line INL may be formed in the same process as thebottom metal layer BML, and may include the same material as the bottommetal layer BML. In addition, although not shown in FIG. 6, the drivingvoltage line VDL (see FIG. 5) and the common voltage line VSL (see FIG.5) may also be formed in the same process as the bottom metal layer BML,and may include the same material as the bottom metal layer BML.

A buffer layer 111 may be arranged on the bottom metal layer BML, thedata lines DL, and the initialization voltage line INL. In other words,the buffer layer 111 may be disposed between the bottom metal layer BMLand the first thin-film transistor T1, and may cover the bottom metallayer BML, the data lines DL, and the initialization voltage line INL.The buffer layer 111 may improve a flatness of the upper surface of thesubstrate 100, and may prevent impurities from the substrate 100 or thelike from penetrating into the first semiconductor layer A1. Forexample, the buffer layer 111 may include an inorganic material such assilicon oxide, silicon nitride, and/or silicon oxynitride.

An interlayer insulating layer 113 may be arranged on the buffer layer111. The interlayer insulating layer 113 may cover the first gateelectrode G1 of the first thin-film transistor T1, the first capacitorplate CE1 of the storage capacitor Cst, and the branch line BL. Theinterlayer insulating layer 113 may include, for example, an inorganicmaterial such as silicon oxide, silicon nitride, and/or siliconoxynitride.

The node connection line NCL may be arranged on the interlayerinsulating layer 113. For example, the node connection line NCL mayinclude Cu, A1, Pt, Pd, Ag, Mg, Au, Ni, Nd, Ir, Cr, Li, Ca, and/or Mo.The node connection line NCL may have a single-layer structure or amulti-layer structure including the materials described above.

As described above, the node connection line NCL may electricallyconnect the first thin-film transistor T1 with the pixel electrode 210to be described later. To this end, the node connection line NCL may beconnected to the source area or the drain area of the firstsemiconductor layer A1 of the first thin-film transistor T1 through thesecond contact hole CNT2 which is defined in the interlayer insulatinglayer 113, and may be electrically connected to the pixel electrode 210thereabove by a contact metal CM.

In an embodiment, the node connection line NCL may include the secondcapacitor plate CE2 of the storage capacitor Cst. In other words, thesecond capacitor plate CE2 may be provided as a portion of the nodeconnection line NCL. Thus, a space may be used efficiently, and a degreeof integration of the display device 1 may be improved.

The node connection line NCL may be connected to the third capacitorplate CE3 of the storage capacitor Cst through the tenth contact holeCNT10 which is defined in the interlayer insulating layer 113 and thebuffer layer 111. Thus, the second capacitor plate CE2 of the storagecapacitor Cst integrally provided as a single body with the nodeconnection line NCL may have the same potential as the third capacitorplate CE3. As a result, the interlayer insulating layer 113 disposedbetween the first capacitor plate CE1 and the second capacitor plateCE2, and the gate insulating layer 112 and the buffer layer 111 disposedbetween the second capacitor plate CE2 and the third capacitor plate CE3may serve as dielectric layers of the storage capacitor Cst. Throughthis structure, a capacitance of the storage capacitor Cst may increase.

In an embodiment, the node connection line NCL may include the repairportion RP overlapping the initialization voltage line INL. An area inwhich the repair portion RP and the initialization voltage line INL maybe defined as the repair area RA.

A passivation layer 114 may be arranged on the interlayer insulatinglayer 113. The passivation layer 114 may cover the node connection lineNCL. The passivation layer 114 may include, for example, an inorganicmaterial such as silicon oxide, silicon nitride, and/or siliconoxynitride.

The contact metal CM may be arranged on the passivation layer 114. Thecontact metal CM may be connected to the node connection line NCLthrough a contact hole provided in the passivation layer 114. Thecontact metal CM may electrically connect the node connection line NCLand the pixel electrode 210 to each other. For example, the contactmetal CM may include Cu, A1, Pt, Pd, Ag, Mg, Au, Ni, Nd, Ir, Cr, Li, Ca,and/or Mo considering conductivity.

A planarization insulating layer 115 may be arranged on the passivationlayer 114. The planarization insulating layer 115 may cover the contactmetal CM and provide a flat upper surface for the pixel electrode 210.The planarization insulating layer 115 may include an organic insulatingmaterial, and the organic insulating material may include, for example,a general-purpose polymer such as poly(methyl methacrylate) (PMMA) orpolystyrene (PS), polymer derivatives having a phenol-based group, anacryl-based polymer, an imide-based polymer, an aryl ether-basedpolymer, an amide-based polymer, a fluorine-based polymer, ap-xylene-based polymer, a vinyl alcohol-based polymer, or any blendsthereof.

The organic light-emitting diode OLED may be arranged on theplanarization insulating layer 115. The organic light-emitting diodeOLED may include a stacked structure of the pixel electrode 210, anemission layer 220, and an opposite electrode 230. In other words, theorganic light-emitting diode OLED may include the pixel electrode 210,the emission layer 220 arranged on the pixel electrode 210, and theopposite electrode 230 arranged on the emission layer 220.

The pixel electrode 210 may include a transparent conducting oxide suchas ITO, an indium zinc oxide (IZO), ZnO, In₂O₃, indium gallium oxide(IGO), or aluminum zinc oxide (AZO). In another embodiment, the pixelelectrode 210 may include a reflective film including Ag, Mg, A1, Pt,Pd, Au, Ni, Nd, Ir, Cr, or any compounds thereof. In another embodiment,the pixel electrode 210 may further include a layer including ITO, IZO,ZnO, or In₂O₃, on or below the reflective layer described above. Forexample, the pixel electrode 210 may have a three-layer structure inwhich an ITO layer, an Ag layer, and another ITO layer are stacked.

An upper insulating film 117 may be arranged on the planarizationinsulating layer 115. The upper insulating film 117 may include anopening 1170P corresponding to a portion of the pixel electrode 210. Theopening 1170P of the upper insulating film 117 may expose a centralportion of the pixel electrode 210. The upper insulating film 117 mayprevent an arc or the like from occurring at an edge of the pixelelectrode 210 by increasing a distance between the edge of the pixelelectrode 210 and the opposite electrode 230. The upper insulating film117 as described above may include, for example, an organic materialsuch as polyimide, hexamethyldisiloxane (HMDSO), or the like.

The emission layer 220 may be arranged on the pixel electrode 210 andthe upper insulating film 117. The emission layer 220 may include apolymer material or a low-molecular weight organic material that emitlight of a color. In some embodiments, the emission layer 220 may bepatterned to correspond to each of the pixel electrodes 210 as shown inFIG. 6, but may be integrally provided as a single body across theplurality of pixel electrodes 210 as necessary.

Although not shown in FIG. 6, a first functional layer arranged belowthe emission layer 220 and/or a second functional layer arranged abovethe emission layer 220 may be further included. The first functionallayer and the second functional layer may be included in an intermediatelayer together with the emission layer 220, and may be between the pixelelectrode 210 and the opposite electrode 230. The first functional layermay include a single layer or multiple layers. For example, when thefirst functional layer includes the polymer material, the firstfunctional layer may include a hole transport layer (HTL), which has asingle-layered structure, and may includepoly-(3,4-ethylenedioxythiophene) (PEDOT) or polyaniline (PANI). In acase where the first functional layer includes the low-molecular weightorganic material, the first functional layer may include a holeinjection layer (HIL) and an HTL. The second functional layer mayinclude an electron transport layer (ETL) and/or an electron injectionlayer (EIL).

The opposite electrode 230 may include a conductive material having alow work function. For example, the opposite electrode 230 may include a(semi) transparent layer including Ag, Mg, A1, Pt, Pd, Au, Ni, Nd, Ir,Cr, Li, Ca, or any alloys thereof. In some embodiments, the oppositeelectrode 230 may further include a layer including IZO, ZnO, or In₂O₃on the (semi) transparent layer including the above-mentioned material.

The organic light-emitting diode OLED may be easily damaged by themoisture or oxygen from the outside and therefore may be protected bybeing covered with an encapsulation layer 300. The encapsulation layer300 may include at least one organic encapsulation layer and at leastone inorganic encapsulation layer. In an embodiment, the encapsulationlayer 300 may include a first inorganic encapsulation layer 310, anorganic encapsulation layer 320, and a second inorganic encapsulationlayer 330.

The first inorganic encapsulation layer 310 and the second inorganicencapsulation layer 330 may each include one or more inorganicinsulating materials. The inorganic insulating layer may include Al₂O₃,tantalum oxide, hafnium oxide, ZnO, silicon oxide, silicon nitride,and/or silicon oxynitride. The organic encapsulation layer 320 mayinclude a polymer-based material. The polymer-based material may includean acryl-based resin, an epoxy-based resin, polyimide, and polyethylene.The acryl-based resin may include, for example, PMMA, polyacrylic acid,and the like.

Although not shown in FIG. 6, the color-conversion-transmitting layer500 (see FIG. 2) described above with reference to FIG. 2 may bearranged on the opposite electrode 230 of the organic light-emittingdiode OLED. In addition, the color filter layer may be arranged on thecolor-conversion-transmitting layer 500.

FIGS. 7A and 7B are cross-sectional views schematically illustratingoperations of a method of repairing a display device 1, according to anembodiment.

FIG. 7A shows the display device 1 during a repair process, and FIG. 7Bshows the display device 1 after the repair process. In FIGS. 7A and 7B,the same reference numerals as those of FIG. 6 denote the same elements,and redundant descriptions thereof will be omitted.

Referring to FIG. 7A, when a defect occurs in the pixel circuit PC (seeFIG. 5), the repair portion RP of the node connection line NCL of thecorresponding pixel circuit PC and the initialization voltage line INLmay be shorted to each other. To this end, in an embodiment, a laserbeam may be irradiated to the repair portion RP in which the repairportion RP and the initialization voltage line INL overlap each other.

For example, a type of laser used may be an excimer laser. For example,the excimer laser may have a short wavelength of about 308 nm. Inanother example, types of the laser may include a CO₂ laser, a YAGlaser, a nanosecond laser, a femtosecond laser, a Bessel beam, or aGaussian beam.

In FIG. 7A, the laser beam is irradiated from a lower surface of thesubstrate 100 to a direction facing the node connection line NCL (forexample, along a +z direction), but the present disclosure is notlimited thereto. For example, before the organic light-emitting diodeOLED is formed, the laser beam may also be irradiated from the nodeconnection line NCL to a direction facing the upper surface of thesubstrate 100 (for example, along a −z direction).

Referring to FIG. 7B, the repair portion RP of the node connection lineNCL and the initialization voltage line INL may be shorted to each otherin the repair area RA. For example, as the buffer layer 111 and theinterlayer insulating layer 113 absorb a laser beam, a hole penetratingthrough the buffer layer 111 and the interlayer insulating layer 113 isformed, and the repair portion RP of the node connection line NCL may beconnected to the interlayer insulating layer 113 therebelow through thehole. In this case, the initialization voltage line INL does not gothrough a thin-film transistor, but may apply an initialization voltageto the pixel electrode 210 of the organic light-emitting diode OLEDthrough the node connection line NCL. Thus, the organic light-emittingdiode OLED may not always emit light, and the corresponding pixel PX mayinclude a dark spot. Thus, a bright spot defect may be resolved.

FIG. 8 is a plan view schematically illustrating pixel circuits providedin a display device 1 according to another embodiment, FIG. 9 is across-sectional view schematically illustrating a cross-section of thedisplay device 1 in FIG. 8, taken along line IX-IX′ in FIG. 8, and FIG.10 is a cross-sectional view schematically illustrating a cross-sectionof the display device 1 in FIG. 9 after a process of repairing of thedisplay device 1. Redundant description of the elements previouslydescribed above with reference to FIGS. 5, 6, 7A, and 7B will beomitted, and differences will be mainly described below.

Referring to FIGS. 8 and 9, the display device 1 may further include anauxiliary line AL extending in the same direction (for example, along ay direction) as an extension direction of the initialization voltageline INL. In an embodiment, the auxiliary line AL may be arranged tooverlap the initialization voltage line INL in a plan view. Theauxiliary line AL may be between the repair portion RP of the nodeconnection line NCL and the initialization voltage line INL in across-sectional view. The auxiliary line AL may be formed in the sameprocess as the first gate electrode G1 of the first thin-film transistorT1, and may include the same material as the first gate electrode G1.

For example, the auxiliary line AL may be electrically connected to theinitialization voltage line INL through an eleventh contact hole CNT11provided in the buffer layer 111 and the interlayer insulating layer113. The auxiliary line AL may perform a function of transferring aninitialization voltage along with the initialization voltage line INL.Through the auxiliary line AL, an overall resistance of theinitialization voltage line INL may be reduced, and thus, an RC delaymay be reduced.

Referring to FIG. 10, by irradiating a laser beam to the repair area RA,the repair portion RP of the node connection line NCL and theinitialization voltage line INL may be shorted to each other, but therepair area RA may be electrically connected to the initializationvoltage line INL through the auxiliary line AL therebelow. In otherwords, a portion of the auxiliary line AL located in the repair area RAmay function as a connection member of the repair portion RP and theinitialization voltage line INL. In this case, for example, a hole forthe short may be formed only in the interlayer insulating layer 113, andthus, a quicker and easier repair may be performed.

FIG. 11 is a cross-sectional view schematically illustrating across-section of the display device 1 in FIG. 5, taken along line VI-VI′in FIG. 5, according to an embodiment. FIG. 12 is a cross-sectional viewschematically illustrating a cross-section of the display device 1 inFIG. 11 after a process of repairing of the display device 1. Redundantdescription of the elements previously described above with reference toFIGS. 6, 7A, and 7B will be omitted, and differences will be mainlydescribed below.

Referring to FIG. 11, the pixel electrode 210 may include a repairportion RP′ overlapping the initialization voltage line INL in a planview, but the repair portion RP′ may not overlap the opening 1170P ofthe upper insulating film 117. For example, the repair portion RP′ maybe covered with the upper insulating film 117. At least the repair areaRA, which is an area in which the repair portion RP′ of the pixelelectrode 210 and the initialization voltage line INL overlap eachother, may not overlap the opening 1170P of the upper insulating film117.

Referring to FIG. 12, the repair portion RP′ of the pixel electrode 210and the initialization voltage line INL may be shorted to each other.For example, a laser beam may be irradiated to the repair area RA tothereby connect the repair portion RP′ of the pixel electrode 210 andthe initialization voltage line INL to each other. In this case, theinitialization voltage line INL does not go through a thin-filmtransistor, but may directly apply an initialization voltage to thepixel electrode 210 of the organic light-emitting diode OLED. Thus, theorganic light-emitting diode OLED may not always emit light, and thecorresponding pixel PX may include a dark spot. Thus, a bright spotdefect may be resolved.

Although the display device and the method of repairing the displaydevice have been mainly described, the present disclosure is not limitedthereto. For example, it may be understood that display manufacturingmethods for manufacturing such a display device also fall within thescope of the present disclosure.

According to an embodiment configured as described above, a displaydevice in which a bright spot occurring due to a defective pixel circuitmay be repaired into a dark spot, and a method of repairing the displaydevice may be implemented. According to an embodiment, a simpler andquicker repair may be performed, and thus, the productivity and yield ofthe display device may be improved. In addition, design restrictions onthe display device for repair may be minimized, thereby implementing adisplay device of a high resolution. However, the scope of the presentdisclosure is not limited by this effect.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments. While one or more embodiments have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope asdefined by the following claims.

What is claimed is:
 1. A display device comprising: a substrate; athin-film transistor arranged on the substrate and including asemiconductor layer and a gate electrode overlapping at least a portionof the semiconductor layer; a pixel electrode arranged on the substrate;a node connection line configured to connect the thin-film transistorand the pixel electrode to each other; and an initialization voltageline arranged on the substrate and extending in a first direction,wherein the node connection line includes a repair portion overlappingthe initialization voltage line in a plan view.
 2. The display device ofclaim 1, further comprising a data line arranged on the substrate andextending in the first direction, wherein the initialization voltageline is arranged closer to the thin-film transistor than the data linein a plan view.
 3. The display device of claim 2, wherein the nodeconnection line does not overlap the data line in a plan view.
 4. Thedisplay device of claim 1, further comprising a storage capacitorincluding a first capacitor plate and a second capacitor plateoverlapping each other, wherein the first capacitor plate and the gateelectrode of the thin-film transistor include a same material, and thesecond capacitor plate includes a portion of the node connection line.5. The display device of claim 1, further comprising a bottom metallayer arranged between the substrate and the semiconductor layer of thethin-film transistor.
 6. The display device of claim 5, wherein theinitialization voltage line and the bottom metal layer include a samematerial.
 7. The display device of claim 5, further comprising a storagecapacitor including a first capacitor plate and a third capacitor plateoverlapping each other, wherein the first capacitor plate and the gateelectrode of the thin-film transistor include a same material, and thethird capacitor plate includes a portion of the bottom metal layer. 8.The display device of claim 1, wherein the repair portion of the nodeconnection line is connected to the initialization voltage line througha contact hole.
 9. The display device of claim 1, further comprising: ascan line extending in a second direction crossing the first direction;and a branch line extending in the first direction from the scan line.10. The display device of claim 9, wherein the scan line, the branchline, and the gate electrode of the thin-film transistor include a samematerial.
 11. The display device of claim 1, further comprising: anemission layer arranged on the pixel electrode; an opposite electrodearranged on the emission layer; a color-conversion-transmitting layerarranged on the opposite electrode; and a color filter layer arranged onthe color-conversion-transmitting layer, wherein thecolor-conversion-transmitting layer converts light of a first coloremitted from the emission layer into light of a second color differentfrom the first color, or transmits the light of the first color withoutcolor conversion.
 12. The display device of claim 1, further comprisingan auxiliary line disposed between the repair portion of the nodeconnection line and the initialization voltage line, and electricallyconnected to the initialization voltage line.
 13. The display device ofclaim 12, wherein the auxiliary line and the gate electrode of thethin-film transistor include a same material.
 14. The display device ofclaim 12, wherein the repair portion of the node connection line iselectrically connected to the initialization voltage line through theauxiliary line.
 15. A display device comprising: a substrate; athin-film transistor arranged on the substrate and including asemiconductor layer and a gate electrode overlapping at least a portionof the semiconductor layer; an initialization voltage line arranged onthe substrate and extending in a first direction; a pixel electrodearranged on the substrate and electrically connected to the thin-filmtransistor; and an upper insulating film arranged on the pixelelectrode, and including an opening corresponding to a portion of thepixel electrode, wherein the pixel electrode include a repair portionoverlapping the initialization voltage line in a plan view, and therepair portion does not overlap the opening of the upper insulatingfilm.
 16. The display device of claim 15, further comprising a data linearranged on the substrate and extending in the first direction, whereinthe initialization voltage line is arranged between the data line andthe thin-film transistor.
 17. The display device of claim 15, furthercomprising a bottom metal layer arranged between the substrate and thesemiconductor layer of the thin-film transistor, wherein theinitialization voltage line and the bottom metal layer include a samematerial.
 18. The display device of claim 15, wherein the repair portionof the pixel electrode is connected to the initialization voltage linethrough a contact hole.
 19. A method of repairing a display device whichcomprises: a substrate; a thin-film transistor arranged on the substrateand comprising a semiconductor layer and a gate electrode overlapping atleast a portion of the semiconductor layer; a pixel electrode on thesubstrate; an initialization voltage line arranged on the substrate andextending in a first direction; and a node connection line electricallyconnecting the thin-film transistor and the pixel electrode to eachother, and comprising a repair portion overlapping the initial voltageline in a plan view, wherein the method comprises short-circuiting therepair portion of the node connection line and the initializationvoltage line to each other.
 20. The method of claim 19, wherein theshort-circuiting of the repair portion of the node connection line andthe initialization voltage line to each other is accomplished byirradiating a laser beam to an area in which the repair portion of thenode connection line and the initialization voltage line overlap eachother.